P0340 and P0401

I went by autozone today to rent an OBDII cause my explorer has had some issues (97 5.oL)

It idles somewhat rough and when you stab the accelerator it almost stalls out and then catches and revs back up

The code I pulled was P0340 Camshaft pos sensor circuit malfunction
-where exactly is that located and how difficult is it to install?


As far as the EGR code (P0401) I have read something about the DPFE sensor being bad. Should I try that first and where is it haha? Im sooo frustrated cause the car is running like crap.

Re P0340:
There is a sensor driven from the camshaft which tells the ECU when TDC ,piston No1 firing stroke is occuring. The drive unit can fail (there are two types with Ford I believe) which means that no signal is generated from the sensor. Also the actual sensor itself (retained by 2 small bolts on top of the drive unit, which looks like a small distributor). Once you find the unit, take off the sensor & there should be a vane inside (hall effect unit) which stands up about 1/2" & is semicircular ,this is what triggers the sensor. If it's not there then you need a new CMP drive unit. If it's good then either the sensor is junk or the wiring connected to it is defective. The sensor on mine cost about $30. The drive unit I got from a wreckers for $45, it had the sensor on it ,which worked!! so I was able to return the new unused sensor I bought & the fix cost just $45....LOL.
HTH,
Aeroman.

P.S. Fords will still run with a failed CMP sensor but injector timing (SEFI) will not be firing as sequential but will go to "bank fired". Which is not quite as good but still works good enough to run the engine. I have heard of erratic idling when the CMP fails due to this very problem.

should I try cleaning the sensor first and see if I get lucky?

If not is the sensor easy to change. I have had this truck for 2 years now and this is the first problem Ive had with it so pardon if I sound uninteligent on the subject.

Not at all !!!
If yours is a hall effect unit you should see a small magnetic looking piece, which is what the semicircular vane induces an impulse to. If the magnet is gone, (you'll likely know straight away since there will be a pile of dust & crumbled plastic inside the sensor cavity).

The sensor is very easy to change but if the drive unit has to be replaced then it has to be re-timed, or the injector timing could be off & your CEL will stay on.

Regards, Aeroman.

So the average joe is gonna have a hell of a time changing the drive unit? You wouldnt by chance have a part number for the sensor do you?

I also read this in another thread but Im not sure exactly what it means...


I had the same problem with my '00 Merc mountaineer. P0340 kept coming up, even after replacing the cam sensor, wiring to the PCM, 2dry ign cables, sp plugs, head gaskets, swapped coils, geez... still came up every time I cleared it- it would run for the first trip, with no CEL turned on, then as soon as I started it, CEL is on and it is the P0340, again. Finally, I read on another forum that the problem may be the alternator. I just put a new one in about a month before the problems all started. How to diagnose: Charge up the battery. Clear out the codes. Run it until the P0340 shows. Bring it back home. Clear out the codes. Disconnect the alternator. Yes disconnect the alternator. Isolate the battery terminal at the alternator from any short circuits by wrapping it in elec tape. Take the car on the same trip. If the code does not set on, you found the problem. The voltage regulator is transmitting stray AC voltage that is being picked up by the cam sensor or the PCM and throwing the whole system off. Do the test in daylight with no loads on--no radio, no headlights, no blower. I didn't believe it was possible, but now I am a believer. -Mac

It's not that hard , but needs a little bit of mechanical skill;
Read this & see if it helps;

http://autorepair.about.com/library/a/1h/bl025h.htm
You can also buy a setting tool (#6) to help install the drive unit synchroniser(#2), I have one which fits the 3-4 litre engines but the 5L is different, so cant help on that one.

Regards Aeroman

Just saw your other post, I've heard of that problem but it was a damaged synchroniser on mine & it might be on yours too, you'll just have to look & you'll know!

syncronizer? haha. THis just baffles me. I guess I start at the sensor and go from there and Ill soon find out what in the world is wrong.

Yeah,... synchroniser=drive unit. You can pick the entire thing up at a wreckers for under $50. Just take the sensor off before you buy to make sure that the insides are still intact. (that is if yours is damaged, it could just be the sensor!).

ok, i really appreciate the help. This is the only forum that I have gotten quick replies so far, thank you.